Outlet guiding arrangement



y 1952 A. BUCHI 2,596,647

OUTLET GUIDING ARRANGEMENT 4 Sheets-Sheet 1 Filed Oct. 17, 1951 4b 21 16' 17 22 14 11 14, a 14m 8 4 Flat? Mwavram May 13, 1952' A. BUCHl OUTLET GUIDING ARRANGEMENT 4 Sheets-Sheet 2 Filed Oct. 1'7, 1951 May E3, 1952 A. BUCHI 2,596,647

OUTLET GUIDING ARRANGEMENT Filed Oct. 1'7; 1951 4 Sheets-Sheet 5 qlll/ L f l Mil EN r02.

y 13, 1952 A. suca-u 2,596,647

OUTLET GUIDING ARRANGEMENT Filed 0st. 17, 1951 '4 SheetsSheet 4 \XM- W Patented May 13, 1952 U NI T E D S TTES? AT EN OF E LCE 2,536,647 OUTLET, GUIDlNG Aana o E- 'r A m Bnehi,.Winterthur, Swami,

Applica iOIIQOtObGRl", 1951, SerialNo.'251,742i In Switzerland March-{$1946 3 13 Claigps (Cl. 103 1 03) This invention;relatestoimprovements input-'- let guidin'gt arrangements 'for 'centrifug'al blowersl andlpumps. Thislap'plication constitutes a .con tinuationi-in-part of my application seriaixNo. 732,639jfiledMarch'. 51', IMI'WhiChhas-bee'n afoan;- 5 e i A M a AS'I .havespointedioutain myr'copending'aapplicae tion Serial No. 251,741, filed on the samedat'eheree withpvthe: efiiciencyi' of; a: centrifugal pumpxii'o'r v blower; depends not: 0n1y;u'pon such'ifactors :"as; direction: and .at:substantiallyithesaine velocity; therotor s'p'eed; bearing friction, rotor discafricthereby tot-minimize:impact:1osses: i tiori, shock: losses iat: the; rotors intake andtoutlet; Itis also an object to "effect the: circumferential; butalso iipon; the xductiarrangement whereby the deflectiohioftthefiuidtstreamsiinto thetscro-llspace fiuid1l'eaving=th'e"periphery' cf'the:rotor blading: unde'ntheiwi'destradius-oftrcurvaturen under high pvelocityand inza direction. having' a: 'It is aifurther objectzto'providei'aidevicewhichl substantial tangentiahcomponentfis: captured;rits: mayreasily becdiecastin sections and :theneaiter; velocity-converted:into-"pressure, and the fluid: putitogethen' guideictintmoneior more: streams-of, desired: definefluid velocity into pressure before.-i'the *flui'dsl streams are deflected toward the laterally; offset scrollispacejthereby to.reduce.iflow.losses;

It is also an object to permitsthezintroduction; of the several fluid. streams :into. the scrollzspacer. in such'nmannergrthat; atithe timeithey'ijoin the; stream or streams: alreadyflowing in thaxscroll These and other" objects .zmau be attained; by. tion:;and; direction: It'is desirablei'that :such a. the: apparatus hereafterdest'zribescl'liin which is; guidetductarrangementt effectra smoothrand: 20.:sho'wn:in'* shock'efree: flowv of the "pressures fluid within a: Fig-'1, an axiallsectionithrough a;single minimum; passage length and; such is .1 a; primary"; blowen: taken on'the" line;I-*I,;of:1i?ig.:2 i object; of;.'1nyvinvention-: Fig:2,:an-raxial.view':of. theqblower'shownin In my; aforementioned. copending application, Fig; 1'; :taken1from:the' righthandsi-deivof; and onra I have. described; andtlain'i'edmertaih. inventions-1.25 plane;of"junotur e .II -II;-* relating ,to: outlet gu'iidingfarrangements .forcen= Fig; 2a, atviewin :section of; one ofthe difiusers: trifilgajl;"blowers;andpumps:l Inithisl'application, I shallijdescribe; and claim 'other'inventionsxelat x ing: to V difie'rent" arrangements, of? this gene'ral. ct -l .w A T .1 I.'

My invention described and claimed herein pros vides'in'its preferrediembodiment a-series-of:guide duct difiusers :disposed substantially in" arplan'ep, Rig. .6;a;:section :jsimilait to that/10f: Fig; 4;, but: normaLto-ithe rotortaxisiand vra'diatinggwithr a; illustratings azdifferent'zembodiment .of; my inveni-a substantial tangential componentzfrom the. pei-r tionz'g' 1 riphery:of;:the::blowe1:idisc:r laterally offset .from Fig. 7, in development, a spiral section through; the :blower; rotor; Ii'fiirtheriprovideza ,SCI'OHT case; the. first; guiding passage: and: each subseguent' into-.whichseachtsoirthezguide:ducri'difiusei's;dis, passagatoatheyblower out1et--:header;- charges:itszpressurecfiuidl. "Thistisraccomplished' Fig: 8; a sectionsimilarlto:thati'ofrFig. .7, in an tage;

outsidelof thecblowen housing;

Fig'5213-5, :axial sectionsjthrough the rim: pore accordingftoxsmy present invention-g by dispose 40 embodiment-3" having :twor separate: discharge;

ingcthascrollycasing. in'fsu'chi manner: relative :to; 7

Fig. 9 LandFigi-LlO, an embodiment: of my invent thidifiUSGtiiOlltlGtS thatrta:;portioniofl each; dii'i-1.-' fuser outletieross :sectionf" preferably notfmore; tion in aimultistage blowe'n'fFigz 19 .heing2an1'axiil' than oneeh'alf; lies .inz'thetscioll space; andrfurL-n. section otthehloweniiand FiEZiilQj'Bf-YiBW seen thrbyrextending; and; :shaping; that portion: of; axiaivdirectionzfrom" tllaiilefill' along the-line each difiuse'r'wall' WhiCh'fi'SflfilOSti'IBIIIOteTfrom" i Vlh-VlliofizFig; 9;; i the: scro11i' spaceitO:formra-deflctingcwallrwhich- Fig. I1, an embodiment. is concavelyTcurvedi with respect tov the normal .7 planeinwhich'lie the axes offthedifius'ersz'; This? curvedtw'all; ins'addition'to; deflecting, rthet pressure' fliiidi'ssuing from the diffuserbiwhichj'the wallerepresents anex'tension; may: also. form that portion of the wall of the next succeeding di'finserl in the i'portioniid'i'ofthei blower casing:wh-ichyint-v which'projectszintothe:scrolltspacex this preferred embodiment, isiadditionallyxcon; Ittisyalso 'anobiectotmy-inventiontowpermit. 5.5 stitutediof:the?mating?portionriidefiningxtha bothisidesi." I

a blower 'discrwhich-is keyed'Fontovshaft 22 ""1116 latter:rotatesiwithirrtheibearingji;itself disposed the efiecting: of a substantiallconversion .ofi'the:

space, they are imoving'jin substantially the (same;

seen :by looking at the line :K+Kiof Figure ;2;fror'n:

30 x tions* or the guiding-arrangement and:the:.- scroll f case; taken; respectively: On'rthe; 1ines 1-II,I; III;

in; a single-stage; blower,: the blower'pdisc. o1: awhichz:isibiadedi omi In Fig: Lthe. referencexcharacten 1 represents.

blower intake. These two portions are detachably secured together by means, such as bolts 28'. About the periphery of the blower disc I, I preferably provide an annular clearance gap in in which the pressure fluid is received from the blading la. Leading off from this gap l are a series of openings II into which the fluid is passed. Each of these openings ll communicates with a guide duct diffuser arrangement 6 having its axis lying substantially in a plane IIII (Fig. 1) normal to the blower axis. In the preferred embodiment shown in Figs. 1 and 2, the diffuser arrangement is constituted of a first rectilinear portion I3 and a second curvilinear portion 14. The latter opens at 1 into a scroll space 8a defined by the scroll case portion 8 of the blower casing. This scroll space 8a is laterally offset relative to diffuser arrangement 6, and is further provided with a pressure header 9 into which the fluid stream moves after it has been collected in the scroll space 8a from each of the diffuser outlets 1.

The character l2 denotes a cylindrical port of entry to the rectilinear diffuser I3 which I preferably include to reduce vortex action. After the pressure fluid flows through the rectilinear diffuser portions I3, it passes through the transitional area, points of which are indicated by It and I1, and thence through the guide-passage portions l5. The latter having no defining walls beyond 1 on the side of the scroll space 8a, the pressure fluid streams simply merging with and becoming a part of the streams collected from preceding guide duct passages and moving in the scroll space 8a toward the pressure header 9. On the opposite side from the scroll space 8a, each guide passage portion 15 is defined by a deflecting wall [5a which commences as an extension of the wall Ma (defining the curvilinear diffuser portion) and curves axially of the blower towards the scroll space 8a concavely with respect to the plane IIII which is normal to the blower axis and in which lie the axes of the diffuser arrangements 6. This curved wall 15a curves gently to deflect the fluid stream issuing from the diffuser portions 14, into the scroll space 8a where it joins with minimum turbulence and impact, the streams previously collected and moving in the scroll space 8a. It should also be noted, that in my preferred construction, the portion 15b of the wall l5a which is radially outermost of the blower is brought adjacent the radially outermost portion 8b of the scroll casing 8. The portion 8b is flattened and extended axially of the blower to meet [5b beginning at the points of transition Moreover, I also shape the inner portion 8c of the wall of scroll casing which is adjacent the guide duct arrangement 6 so that it merges with the inner portion 150 of the duct defining wall 15a, which is radially innermost of the blower axis, beginning at the points of transition 16, I1.

The manner in which the blower housing sections 4, 5 and guide duct diffuser defining walls 13a, [4a are preferably integrated with the scroll casing 8, is illustrated in the several sections of Figs. 3, 4 and 5. From these sections it will'be seen that, in order to keep the pressure fluid moving in the scroll case at substantially the same speed as it is moving from the several curved guide duct diffuser outlets in accordance with one of the prime principles of my invention, it is necessary to maintain at least constant the cross sectional areas of the scroll space where each succeeding diffuser. arrangement approaches the radially outer scroll space portion into which the pressure fluid is discharged as heretofore described. Moreover, to accomplish the object of maintaining constant speed of the fluid throughout the whole extent of the scroll space, it will be seen from Figs. 1, 2 and '7 that I provide a predetermined increase in the cross-sectional areas of the scroll space as the stream from each diffuser joins the streams previously collected therein.

The pressure header 9 into which the collected pressure fluid streams pass from the scroll space may be constructed either as a diffuser-like header E8 or as a parallel wall l8 (shown by dash-and-dot lines in Fig. 2), depending upon whether it is desired to effect a further conversion of the fluid velocity into pressure or to maintain the pressure heretofore created by the difiuser ducts.

In laying out the scroll space M and pressure header 9 with respect to the several guide duct diffusers 6, I preferably arrange one guiding passage ll, I2, 13" and 14" to constitute the origin of the scroll space, and at least the last of the succeding guiding passages ll", l2", l3", l4" (emptying into the same header) to open directly into the header 9 in a substantially identical discharge direction.

While my invention will attain its objective quite satisfactorily without them, I have thought it desirable in some instances to provide curved guide vanes I41 in the curved diffuser sections in order to obtain relatively greater radii of curvature in the duct passages, especially at points of greater deflection. When vanes of this type and purpose are provided, I place them preferably at right angles to the abutting faces of the two sections 4, 5 which, when brought together, form the blower housing and the guide duct diffuser arrangement. These vanes I41 may each be constituted of two sections Mia, I411), one section being disposed in each half of the duct defining wall Ma, and the two sections l4la, l41b being constructed to join with each other in the plane of separation. In one of the diffuser sections M in Figs. 1 and 2, I have shown such a vane construction. These vane sections may be cast integrally with the duct defining wall Ma, or slotting M2 may be provided into which the vane sections may be inserted after the casting and machining of the duct walls.

As above indicated, in my preferred embodiment, my guide duct arrangement and scroll casing are constructed of at least two sections 4, 5 divided by and intended to be brought together along a plane IIII substantially normal to the rotor axis as shown in Fig. 1. I have stated above that bolts 20 serve to secure together these two sections. It is a further feature of my invention that these bolts 20 or other screw connections be disposed in the areas I 9 between the guide ducts, which areas have a substantial extent radially of the blower axis. Such'disposition of the bolting 20 insures a good juncture of the two sections 4, 5.

This manner of securing the casing sections 4, 5

may be supplemented by providing further screws or bolting 21 about the casing periphery, disposed in areas between the discharging outlets of the several curvilinear diffusers l4, and by providing interengaging shoulders 4b, 5b in the casing periphery (Figs. 2, 4). It would also be possible to employ peripheral bolting without the internal bolting 20.

The guide passage scroll case arrangement of my invention may also be constructed of. three imm ithcdimentssectien r 415:; registry, form the blower dis hops monster; 8" whcnpronerhc J. V. IlQdi; constitutezt eg dischargaexitsanokscrollspacadisp se V. m ito myinventioni: Thcsadvanta ao ,thisz segtinnal construction; isthatall. hre tsectionsa may;begmanufactured Without:casting about-cores: forahollow spaces iaea; they may bei-die vcastmrzrlo pressed;out-;-or: sheet-"material; In ;this;aa=rrang ment-,-;the section :8 may-be .securechtoj '5 bystu boltsandinutsfl,orifby any. other-isuitableiinean In putting together this three-sectional embodia, ment, .secti-ons;4; 5f andaB'; should-first beLcerL- l5 tered axially with'resnectztoi eachothers and-then fixed; in raecireumferentia-lt-J direction :..-relative: to; each other to ensuraaepcsitiyefiti; V

The'manner in whichmressurefiuid leavin'gethe rotor blading Ia passes through my guide duct:.: arrangement to the: pressure header outlet; St may be seen quite clearly in Fig: 7;: Upon leaving thev bladingla-,\-the:.fluid is first-impelled intoithe gap: l 0 from whence it enters the initial Jgu-idepassage li thecomponents H, l2, l3, ldof which have -been heretofore fully described The axes of all of these: components,- as: previously men-:- tioned, lie substantially in the plane II II which is disposed normal to theblower-axiss When the fiu-id leaves the' outlet 1' of-'thecurvilineandiffuser: portions l 4; it passes-into the --passage-portion= l5 where it 1 is deflected axially-of the a blowerby the wall I twat a great radius of-curvature and into the axially ofiset scroll space'fia overthe outside wall defining the guide passage portions [3 -1 5' of--the -ne'xt succeedingguide duct arrangement;- Each' succeeding guide duct arrangement-tune tions in the same manner. All streamsare thereby broughtinto the scroll space 8a; one after anothen -joining the preceding streams as they move-toward the pressure header 9:-

Itshouldl be stressed at this point that 'the 1 passage 'portionl 5 should preferably be-so dimensioned:asto-smaintain over its entire cross sec tion: themsame. velocity as vprevails in the cross as section I of the outlet of the curvilinear diffuser: portion; 14;: Moreover; theinflection; commencing at; the; point; 24 shouldbe: givenavradius. of J cur-l. vaturezof such' length lassto decreaseethei transb a tional elosses whichnormallyawould: arise the:. fluid; moves; through passage ,portionr. l 5 :into -.;the': scroll-spaceiflai; Inlthis, preferrednlayoutdntere engaging-shoulders 22 are produced -,in;portiona4z Qra-tha; wall of the; latter clos y approaches; the-plane-ofjunctureIk-II .oflportions. 4.:and 5. hese; houldersg zim y. e uscdfor locating: the; nn ct n means seen Fi s; 2 .lanulnwso antne aconnmfinamaus? l d passed throu h. any por ions uidgms eswa Als i-as E QU1JZ f QiQ$ QLt EQ; Z-$ 1% @1 of the; scroll should preferably be shaped and v nSlQnedf1 o, subs ntially: ual; el cit es.- throuehout,tiieqscrollspa rBa Toaaccom-nli h; thi's, .thercross-rsectional area of thescroll' space .65 at; or am les 261 s d e qua to the, cross=sectional area on the ,curved difiuser .disev at l; V and t ecrcs ectionala easi-at-l. points' 21+3fl, should be respectively substantially two, three, four and five times asnlargega;v

In the Fig.-- 8 arrangement, a two separate scroll case portions fi, andB have beenprovided whichp r e s ea o ect-pressure.fl id fr m t ree: ide-m ssa es sand-pass t o e t dtfluidxre- 1 speetiyel gintoheaders 9fand--,9'-'-' These sepa- 76 F gazQ andilol. Referenceacharacters I; il.-f l f:"'andi.

lf--= designate that fourzrunners; keyed w'ontoithe shaftrznwhich shaft turnsj'withimthmbearings and 33, Thejsuctiorr-intake jadesignatedz-byei and the pressure header by l8. It willbe;notech frorm Eiga-'lmthat.fivexguiderpassagesarei provided. for: collecting the;pressur erfiuid fromreaxzh'runnerzi Itgwilltbeiseenfrom'ii'giilxthat thevcross -section&,.; of the: scrolliicasessa; I th'nand 8 "'"aresmadesubstani-- tiallyi-equaliat their narrowestapoints inallaradialia sections?- Moreoven: onl-yi the leading passage b1?" eachiset: 0t five guideg p'assagess hast-ta deflects;- theiawfluidaxia11y intothe scroll spacer Em a each-scroll- :case -8; 8 andl8'-'-; the pressure fiuidf is nonducted:by thevanes 3 2t: 32 and -S2 respe tivelya into :the inner collectin chamber: 33; SS- and 33 ofthe nextiblowenstage. The lastscroil case-3 may be of' adesign similarto-that the-blower of Fig, 1" with an increasing-flow pro---- file.---

the embQdimentof' Ei-g. 11, the runner bis bladed on both sides; each being. fed-by a separrate intake 3 1 The pressure fluid dischar-ged by-- thisdouble-bladed runner is collected b'y a-guide passage arrangement which may --be simi1ar to; the arrangement of-Fig; 1 with a-single-=-scrol3 case and pressure; header, or it may comprise-a dual-series scroll; such as is-illustra-ted --in- Fi g. 8 with twoheaders lsand l8 as-shown in Fig. -1

While I- have shown and described several'di ferent types ofsingle stage blowers-ineali of which thescroll is-disposed laterally-ofis et to wards the blower intake; this is -simplyra; matter ofchoice and it will-be obvious"-that the scroll may be laterally offset towards the opposite side fromthe intake just as-is normally'the-case multistage-blowers- (see Fig; 9).

1. In a centrifugalpump or-blowerhaving-a bladed rotor and a casing enclosing-said"rotori anoutlet guiding arrangement for delivering pr r fl i v r m a d" ro or nc uding u: rality of guide ductpdiiiusers receiving thep re fl id deli er d: b th ater blad i e s, f sa d ifiusers" l in subs a l ane mal t he 'O le ai. a p rtion efin n ias r ll spa e, sai 5 at "least art a at ally 'ofis tfrqm, ed ubs an a aral e o a ap neash 1 portion further partially; cleanin the, ,duiusen tlets; said Out ets ex din at least =partia1-1y. into said scroll sbace and being directedsubstari tially parallel withthe direction of fi'oyv. in the; scroll space, said, casing portion. further including, a a deflecting wall for each diifuser, sjeuld;wall:v e.-. ginning at that side, most remote, from the; centralarea of the scrollspacapf th outle'tf hudifiils and ai efl i a a l b in Iona cavcl cu ved wi h es ec t ai P ns. and extending atleastpartially axially vof theEbI 'weiinto the, scroll spaca, whereby v the,;.press urea ii is deflected into said partially offsetscroll snacer 2,; Theoutlet guiding arrangement as described in claim .1 wherein the'dlffusers have, for at least part of their ,xtent, curvilinear axes, said curving in a: direction circurnscribing the. The outlet-e ding-armea ment 2 in claim-.2 Wl a least .--.ro e:sii: e;v d pqse n ti ls-curv l near DREW??? Qteaeh s t fuser, said guide vane being curved in tangential direction and with the axes of said diffuser.

4. The outlet guiding arrangement as described in claim 2 wherein at least one guide vane is disposed in the curvilinear portion of each diffuser, said guide vane being curved in tangential direction and with the axis of said diffuser, each of said diffusers and each of said guide vanes being divided into two parts along said normal plane, one part being disposed on each side of said plane.

5. In a centrifugal pumpor blower having a bladed rotor and a casing enclosing said rotor, an outlet guiding arrangement for delivering pressure fluid from said rotor, comprising a plurality of rectilinear difiusers disposed within said casing radially beyond the rotor blading, the axes of said diflusers lying approximately in a plane normal to the rotor axis, a curvilinear diffuser communicating with each rectilinear diffuser through which curvilinear diffuser said fluid is further passed, the axis of each said curvilinear diffuser also lying substantially in said plane, said casing having a portion defining a scroll space, said space being at least substantially parallel to said plane, said casing portion further partially defining the diffuser outlets, said outlets extending at least partially into said scroll space and being directed substantially parallel with the direction of flow in the scroll space, said casing portion further including a deflecting wall for each diffuser, said wall beginning at that side, most remote from the central area of the scroll space, of the outlet of such diffuser, and said deflecting wall being concavely curved with respect to said plane and extending at least partially axially of the blower into the scroll space, whereby the pressure fluid is deflected into said partially offset 4 the axes of all said diffusers lying substantially in a plane normal to the rotor axis, all said diffusers being integrated with the walls of said housing, said housing providing additionally a scroll defining a scroll space, said space being at least partially laterally offset from, and directed substantially parallel to said plane, said scroll further having a radially outer housing wall, the discharge orifices of said curvilinear diffusers being disposed within said space contiguous to the inside surface of the said outer housing wall,

said orifices being directed substantially parallel with the direction of flow in the scroll space, said housing further including a deflecting wall for each curvilinear diffuser, said wall beginning at that side, most remote from the central area of the scroll space, of the discharge orifice of such diffuser and curving at least partially axially of the blower and concavely with respect to said plane into the scroll space to form, adjacent to the radially outer housing wall, deflected passages extending from 7 each said curvilinear diffuser discharge orifice on the side of said plane opposite from said scroll space, into said scroll space, whereby the pressure fluid is directed smoothly over a surface portion of the outer wall of each 8.. preceding diffuser guide-duct and peripherally over an are having a large radius of curvature, into the scroll space.

7. The outlet guiding arrangement as described in claim 1 wherein there is additionally provided outlet header means in communication with the scroll via which means the fluid received in the scroll may be discharged, the said scroll having such cross-sectional dimensions increasing in the direction of the flow that the pressure fluid entering the scroll successively from the curvilinear diffusers is maintained at substantially uniform velocity, and is thus guided into the outlet header means.

8. The arrangement as described in claim 1 wherein the scroll is variably formed to assist in the maintenance of substantially uniform velocity of the fluid flowing therethrough as received successively from the outlets of the several diffusers.

9. The arrangement as described in claim 1 wherein the diifusers and the casing are divided along said normal plane into two sections, said sections having depressed areas between each difiuser and the diffuser next adjacent thereto partially laterally oifset from, and directed to accommodate means within the overall diameter of the casing for securing together said two sections along said normal plane.

10. An outlet guiding arrangement as defined in claim 1 in which the said guide-duct diffusers are constituted of a surface of a first casing part,

said surface being appropriately formed to define a portion of said diffusers, and of an oppositely formed surface of a second separate casing part, said two surfaces being brought together in a plane normal to the axis of the pump or blower to register the corresponding formation of both said surfaces.

11. An outlet guiding arrangement as described in claim 10 wherein one of said casing parts additionally forms by its side opposite said surface, a portion of the wall of the scroll space, said wall portion being discontinued in the areas of the diffuser outlets thereby to provide for direct communication between said diffuser outlets and the scroll space.

12. An outlet guiding arrangement as described in claim 1 whereinthe said guide-duct diffusers are constituted of a surface of a first outer casing part, said surface being appropriately formed to define a portion of said diffusers and of an oppositely formed surface of a separate middle casing part, said two surfaces being brought together in a plane normal to the axis of the pump or blower to register the corresponding formations of both said surfaces, the other side of said middle casing part having a surface forming the wall defining the side of the scroll space adjacent the diffusers, said middle casing part being discontinued in the areas of the diffuser outlets thereby to provide for direct communication between said diffuser outlets and the scroll space, and of a third convoluted casing portion, the last said portion being formed with a surface to provide the remaining wall defining the scroll space and the said side of the middle casing part forming the wall being joined in a second plane normal to the rotor axis with the thus formed wall of the third casing part to register their corresponding surfaces.

13. The arrangement as defined in claim 1 wherein the deflecting wall for one diffuser extends axially of the blower past said plane and into the scroll space, the curvature of said Wall in cross section in the flow direction of the fluid being reversed to convex with respect to said plane beginning approximately where said wall crosses said plane, and said convexly curved Number portion of said wall forms a partial defining wall 2,263,353 for the outlet portion of the next succeeding 5 2,311,024 diffuser. 4 ,04 2,419,669

ALFRED BUCHI.

REFERENCES CITED 10 figg The following references are of record in the 00,4 5 file of this patent: 300,955

UNITED STATES PATENTS Name Date Turner Dec. 30, 1941 Buchi Feb. 16, 1943 Nickerson July 80, 1946 Berman Apr. 29, 1947 FOREIGN PATENTS Country Date Great Britain Oct. 14, 1921 Germany Aug. 19, 1924 France Feb. 19, 1926 

